public class LX2{
	
	public static void main(String[] args){
		
		double score = 78;
		char level = score >= 90? 'A':
		    (score >= 80?'B':
			    (score >= 70?'C' :
			        (score >= 60?'D':'E')));
		System.out.println(level);
		
	}
	
}